Screen



(No Model.) 2 Sheets-Sheet 1.

G. W. CROSS.

- SCREEN. v No. 541,595. Patented June 25', 1895.

IN VE N T0)? ATTORNEYS.

(No Model.)

2 Sheets-Sheet, 2.

G. W. (moss;

SCREEN.

No. 541,595. Patented June 25, 1895.

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UNIT D STATES PATENT OFFICE.

GEORGE W. CROSS, OF PITTSTON, PENNSYLVANIA.

SCREEN.

SPECIFICATION forming part of Letters Patent No. 541,595, dated June 25,1893.

Application filed March 8, 1894:.

To all whom it may concern.-

Be it known that I, GEORGE W. Onoss, of Pittston, in the county ofLuzerne and State of Pennsylvania, have invented a new and usefulImprovement in Revolving Screens, of which the following is aspecification.

My invention relates more particularly to revolving screens such as areemployed for the screening of coal; and its object is to produce ascreen which will be provided with means for tumbling the coal as thescreen rotates, and will be well adapted for all character of work,including the screening of wet coal, in which the acid of the mine waterquickly corrodes the rivets or bolts which have heretofore usually beenemployed to secure the edges of the screen segments together and to theprotector and tumbler plates which have been placedover the seamsbetween the screen segments.

In screens of the character alluded to, the protector and tumbler platessoon become loose and not only fail to serve the purpose for which theyare intended, but permit the opening of the seams between the screensegments where the longitudinal edges abut, and the escape of the finecoal therethrough.

In carrying out my invention I construct the screen segments of punchedsheet metal plates, which, as is well known, possess some degree ofresiliency, and overlap the adjoinin g imperforate margins of suchplates, except at their ends, where they are supported upon the spiderheads or bands the overlapping longitudinal margin on the inner side ofthe seam being ofset and turned inwardly. This inwardly turned edge notonly stiffens the screen segment, but also acts as a tumbler bar toresist the sliding motion of the coal within the ,screen, and to tumblethe coal so as to produce effective screening. The screen segments aresecured at their ends to circular spider heads or bands by bolts, asusual, but no bolts or rivets are employed to connect the overlappingedges between these heads or bands.

When the segments are secured in position, the lap of the edge of oneover the edge of the other prevents the coal from escapingthrough thejoint. As an additional safeguard, however, the screen is rotated sothat the angle formed by the inwardly turned edge at each Serial No,502,870. (No model.)

overlapping seam will take the strain caused by the weight of the coal,theettect of which is that owing to the resiliency of the sheet metalplates the edge of the adjacent segment is protected and the flanged.portion of' the one screen-segment, and Fig. at is a similar viewshowing the joint between two screensegments.

The screen A is usuaily constructed of a number of sections, eachsection being made up of several curved screen segments B which aresupported at their ends by circular spider heads or hands 14. Thesecircular spider heads or bands, are mounted upon a shaft or othersupport 11, rotating in bulk-heads or fixed bearings, 12 and 13 andarranged in an inclined position, so that the coal which isdelivered atthe upper end bya chute 15, travels down the screen as it rotates, andis discharged from the lower end of the screen.

The screen segments B are made of sheet metal plates, punched to provideproper perforations 18 and having an imperforate margin 16.

According to my improvement the adjacent longitudinal edges of thescreen segments B are overlapped, the trailing longitudinal edge of eachsegment being on the inner side of the joint. The body ofeach screensegment on its trailing side is provided with an extension B integralwith the segment, which extension is ofiset inwardly from the body ofthe plate, and is provided with an outwardly turned edge 21 forming anangle or L-shape with the body 20 of "the extension. The extension Bstops short of the imperforate margin16 at .the ends of the screensegments, such ends being provided with shoulders 19, which abut againstthe straight leading side edge of the adjoining screen segment on thespider rim or band as shown in Fig. 4. The screen segments are securedto the circular spider heads or bands 14 by their end margins as shownin Fig. 4, no bolts or rivets being used to secure the overlappinglongitudinal edges of the screen segments between the said heads orhands.

In operation the direction of rotation of the screens is as indicated bythe arrow in Fig. 4. The angle produced by the parts 20 and 21 of theextension B forms a pocket at which receives the coal in the rotation ofthe screen, and the pressure exerted on that angle forces the extensionB outwardly, thus guarding additionally against the escape of the smallcoal through the joint. The absence of bolts or rivets to connect theoverlapping edges between the spider heads obviates the diflicultyarising from the corroding of such rivets or bolts by the acid of themine water.

What I claim is 1. In a rotating screen, the combination of perforatedscreen segments, more or less resilient, and having imperforatemargins,supported at their ends and overlapping but unsecured alongtheir longitudinal edges, the longitudinal edge of the inner plate ateach joint being turned inwardly, substantially as set forth.

2. In a rotating screen, the combination of perforated screen segments,more or less resilient,and having imperforate margins,supported at theirends, their longitudinal edges abutting at the points of support andoverlapping but unsecured between the points of support, the edge of theinner plate at each joint being turned inwardly, and such inwardlyturned edge forming a trailing pocket for tumbling the coal,substantially as set forth.

3. The screen segment B, of sheet metal having a perforated body and animperforate margin 16, one side of the longitudinal edge of the platebeing provided with an angular olfset extension B formed integral withthe body of the plate, and with shoulders 19 at the ends of this side ofthe plate, substantially as set forth.

GEORGE IV. CROSS. Witnesses:

W. M. BERRY, J. OSCAR SMITH.

